Is it possible for my sole sexual partner to have had chlamyida for over six months without passing?

Is it possible for my sole sexual partner to have had chlamyida for over six months without passing it to me? I had a Pap smear and culture testing done six months after I started a relationship with my current partner. All came back negative for stds/chlamyida. A year and a half later I had another well-woman exam and my tests came back positive for chlamyida. I am still with the same partner.